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AS 4654.1 (membrane materials): product spec for external above-ground

AS 4654.1 sets product specs for waterproofing membranes used externally above ground: flat roofs, balconies, planters. Three exposure classes, compliance certificate.

By Dan Waring. Last updated 16 May 2026. Verified 16 May 2026.

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In plain English

AS 4654.1:2012, Waterproofing membranes for external above-ground use, Part 1: Materials, is the Australian Standard that sets the product specification for waterproofing membranes used externally above ground: flat roofs, balconies, planter boxes, podium decks, terraces, and external tanking that does not sit below the water table. It is the product half of a two-part series; AS 4654.2:2012 is the design and installation half (verified 2026-05-16).

Membranes for internal wet areas sit under AS 3740:2021; membranes for below-water-table tanking sit under AS 4858. AS 4654 covers the middle case: outdoors and above ground.

NCC 2022 Volume Two Housing Provisions Part H2D8 calls AS 4654.1 + AS 4654.2 as the DTS pathway for external above-ground waterproofing. A membrane without an AS 4654.1 compliance certificate cannot be used as the DTS solution; it must go via a Performance Solution instead.

What it requires

For the membrane manufacturer:

  1. Exposure class. Each product is tested and classified for the exposure it can endure:
    • Cat I: sheltered, low-traffic.
    • Cat II: general external above-ground (most balconies, flat roofs).
    • Cat III: trafficable, high-exposure (podium decks, planters with permanent water, heavy use).
  2. Material testing. Tensile strength, elongation at break, tear resistance, dimensional stability, UV resistance.
  3. Compatibility with substrates and overlays. The membrane must bond to concrete, fibre-cement, plywood, or the substrate stated; it must accept tile adhesive, screed, or pebble overlay without lifting or curing failures.
  4. Manufacturer’s compliance certificate. A signed certificate from the manufacturer stating the product meets AS 4654.1 to the nominated exposure class. The certificate must be available at install time.
  5. Application data sheet. Per-product technical data covering primer requirements, coat thicknesses (wet and dry film thickness), recoat windows, cure times, and surface conditions for application.

What it doesn’t cover

  • Installation method. That sits in AS 4654.2 (Design and installation). The product spec stops at the can or roll.
  • Internal wet areas. AS 3740:2021 covers shower, bathroom and laundry waterproofing inside the building envelope.
  • Below-grade tanking. AS 4858 covers tanking below the water table; different exposure regime, different product class.
  • Industrial chemical-resistant membranes. AS 4654 is general weatherproofing; chemical-tank linings sit under specialist industrial product standards.
  • Roofing underlays and sarkings. AS 4200 series covers pliable membranes that are NOT the primary waterproofing layer.

Practical implications

  • Substituting a product without verifying its AS 4654.1 class is the most common defect. A Cat II-rated membrane installed where the spec called Cat III (e.g. a trafficable podium deck) will fail at the first heavy use cycle. Read the product data sheet against the design intent.
  • Compliance certificate must be on the project file. The certifier and the waterproofing certificate will both expect it. Some product packaging shows “AS 4654.1 compliant” without a per-product certificate; that’s a marketing statement, not the document the certifier will accept.
  • Cure-window discipline matters more than coat thickness on Cat III applications. Heavy-traffic membrane systems often need 24-48 hours between coats and 5-7 days before screed or tile. Rushing the cure halves the system’s exposure-class performance.
  • UV exposure during the install is built into AS 4654.1. Most Cat II/III products tolerate a short UV-exposed period before being covered (commonly 30 days). Exceeding that window degrades the membrane below its certified performance.
  • Detail compatibility with AS 4654.2. The product and the install method must match. Some manufacturers’ membranes have specific termination details that depart from AS 4654.2’s generic detail library; in that case, the manufacturer’s detail prevails as the system being certified.

References

See also

Last updated: 2026-05-16. Verified: 2026-05-16. Quarterly review for currency.

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